In the art of steelmaking it is well known to provide furnaces for the purpose of heating slabs or billets of steel during forming operations. For example, in steel rolling operation, the steel slabs being rolled must be maintained at a sufficiently elevated temperature to perform the rolling operations. Thus, as the steel slabs cool during extended rolling operations, they must be reheated at intervals to maintain the desired working temperature. To provide such reheating, reheat furnaces have commonly been provided in the form of an elongated furnace enclosure of refractory brick having vertical sidewalls and a slightly arched roof. Such furnaces also have a charging end and a discharge end, and a conveying means such as a walking beam structure which extends within the furnace intermediate the charge and discharge ends to move the workpieces in sequence through the furnace for reheating thereof.
Because such furnaces typically operate at very high temperatures, the enclosures therefor must provide a very high degree of thermal insulation in order to minimize heat loss to the ambient atmosphere. The efficiency of the thermal insulation in such furnace enclosures is, of course, directly related to the cost of reheating operations, and more specifically, to the fuel cost element.
Conventional furnace enclosures, for reheat furnaces such as above characterized and similar structures, typically have comprised a structure of refractory material such as refractory brick, as noted, which provides the requisite thermal insulation for the furnace enclosure. Such furnace structures also have been provided with further support structure such as an external framework of structural steel with hangers from which the refractory structure as well as pipes and headers of the fuel system are suspended. Such structural framework has been required due to the massive weight of refractory material that is required to provide to the requisite thermal insulation. In addition, the requisite network of fuel supply pipes and headers must be supported. For these and other reason, conventional furnace construction has dictated furnace structures as above characterized. Due to energy cost escalation and competitive pressure from lower cost steel making operations, practitioners in the steel making arts have continually sought capital cost improvements for various aspects of steel making operations, including those pertaining to reheat furnace structures and the like.